Security System / CCTV NVR integration

[designsystem 0]

Looking to see if I can connect the security systems to the CCTV system NVR

thinking cause its not possible to get a wire to the alarm panel that instead to break into the negative trigger wire to the bell box and run it into a relay with a 12v positive already there and have the relay send a NC or NO signal to the input of the NVR so that my client can get an alert on his CCTV app and see the footage of the corresponding internal camera

am sure its possible just would like to check with someone whos already done it and if I need a diode or anything